U.S. Army Corps of Engineers’ Portland District is increasing controlled water
releases at most Willamette Valley dams as rain and melting snows are projected
to fill reservoirs to near 100 percent capacity in the coming days.
flows include water release at historic rates from Dorena Reservoir, and the
Corps has worked in partnership with Lane County Emergency Management, which
has issued evacuation notices for those in the Row River Floodplain and the
Coast Fork Floodplain of the Willamette River.
are managing flows in a way to protect the downstream public from flood to the
extent we are able, and to maintain space in the reservoirs to avoid
uncontrollable releases,” said Ross Hiner, Portland District Dam Safety
inflows are so high that we are having to increase our releases to minimize the
overall flooding risk,” he said.
releases mean that the Corps is maximizing reservoir storage within safe
to this rain event, below-average precipitation in the Willamette Valley
contributed to low reservoir levels throughout the system of dams, while snow
levels in the basin were above average.
are currently experiencing an atmospheric river coupled with melting
snow,” said Salina Hart, Portland District Chief of Reservoir Regulation
and Water Quality.
Corps reservoirs are able to capture a portion of the flood waters in order to
reduce downstream flows, but will not be able to eliminate all of its
impacts. Water managers expect levels in
the Willamette Valley to be at flood stage now through the middle of the week
at several gauges, including Goshen and on the main stem of the river at
Harrisburg and Albany.
forecasts show Salem near flood stage Wednesday.
flood stage will result in water inundating areas that are not normally covered
by water, and teams at the Portland District are running forecasting models
multiple times a day in conjunction with the Northwest River Forecast Center.
The models are used to assess forecasted inflows to Willamette Valley
reservoirs and flows from unregulated tributaries to plan reservoir outflows
for downstream flood risk management.
models are rerun with updates to the forecast and the latest information on
projected operations is shared with local emergency managers.
in affected areas should follow the instructions of local emergency managers as
unregulated flows from tributaries continue to contribute to water levels.
the most up to date official river flow information, refer to the Northwest
River Forecast Center at https://www.nwrfc.noaa.gov/rfc/